Ippo sees the hidden shot, the second arrow. From the start, Gonzales was hiding another shot in the shadow of his left fist.

Miyata comfirms that, it's hard to hit someone who ducks a lot with a stright punch. Gonzales intentionally used uppercuts to make Ippo use headslips instead and the result he got was "Ippo dodges left". The important hit on Gonzales's one-two is actually two. He uses this while punching with his left and before pulling it he uses the right and it seems it came from nowhere because it hides the actually punch the (two) right.

Ippo sees the punch but he has no time to dodge so Gonzales hits directly to Ippo's head. Ippo slips back with the power of the punch. Everyone else hears the sound of the punch and all of thinks it was a powerful punch. But then Ippo puts down his leg and knocks his gloves together. Now everyone thinks was that punch had no effect on Ippo. In the crowd Mashiba and Sendou talks, Gonzales almost looks like he is in pain, then Sendou realize Gonzales's right hand. Miyata smiles and mentions back in the day when he fought with Ippo, he did the same think and Ippo stopped with his head like it was nothing. It's simple but also effective. When you have a forehead slammed to your fist, it makes your hand go numb for a while he says. The training Coach Kamogawa gave him comes to Ippo's mind and Ippo starting to believe he can actually has a chance against the number two in the world. Coach Kamogawa also thinks he can actually hit Gonzales.